Many of the current window drive mechanisms used with horizontally projecting windows are large assemblies that have multiple complex mechanisms that increase cost and installation time. In some instances, these drive mechanisms extend around the window frame. These drive mechanisms are bulky and require additional space to retain the drive mechanisms within the window frame or between the window frame and the sash.
Window drive mechanisms with beveled gears are one example of a system useable with horizontally projecting windows. One example of such a drive mechanism is shown in U.S. Pat. No. 4,866,882. The beveled gears translate rotation from a crank to rotating shafts disposed around the window frame. The rotating shafts are threaded and engaged to levers having corresponding threaded collars. The levers are actuated by the rotating shafts to move a window sash to open and closed positions. One disadvantage of this type of drive mechanism is the bulky gearing and shafts needed to open and close the window. The shafts extend around the window frame and take up space between the frame and the sash. Alternatively, the window frame is made larger to store the drive mechanism, requiring additional materials and cost.
Drive mechanisms including chain actuators are another example of a system used to open and close horizontally projecting windows. An example of this type of drive mechanism is shown in U.S. Pat. No. 6,070,637. A chain is looped around the frame and engaged to gears spaced along the frame. The gears include threaded sockets that are coupled to screws coupled to the sash. Rotation of one of the gears through a crank drives the chain which rotates the other gears. The rotating gears translate the sash with respect to the window frame because of the threaded relationship between the sockets and the gears. The size of the mechanism and corresponding size of the frame are a disadvantage with this type of drive mechanism. Space is set aside for the drive mechanism instead of the window, thereby limiting the size of the window or requiring a larger frame. Alternatively, the large drive mechanism is visible and decreases the aesthetic appeal of the window assembly. Moreover, numerous rotations of the crank are required to open and close the sash.
In yet another example, drive mechanisms including scissors linkages and a chain drive are used to open and close horizontally projecting windows. Scissors linkages are disposed on at least two sides of the frame and moveably carry the sash. The chain drive operates to open and close the sash against the frame. The chain drive extends between the frame and the sash at a separate location on the window from the scissors linkages. The chain drive takes up additional space for the window, limiting the size of the window. Alternatively a larger frame is required to house the scissors linkages and the chain drive.
What is needed is a drive mechanism that overcomes the shortcomings of previous drive mechanisms. What is further needed is a drive mechanism that is compact, quick and easy to use.